You can love something without wanting a second helping. Sometimes it's better to let the aftertaste linger. Which science fiction or fantasy movie do you absolutely love — but you wouldn't want to see a sequel to it?

This question comes via trews, as part of today's discussion of the upcoming sequel film 300: Rise of an Empire. Loves 300, doesn't want to see a second movie. Which film do you feel that way about?

Please include a poster or image or trailer for your beloved film (or the uninteresting sequel). And please mention the title and why you think the original should stand on its own.